No oplog tailing, as far as I can tell. Or replica sets or fault-tolerance, for that matter. But I’m thinking of specific use cases along the lines of storing aggregation data and rolling averages. If Mongo is the bookshelfs of the library, then using HyperDex would be a card-catalog system of sorts.
@nathan_muir - thank you very much for sharing TokuMX. I wasn’t aware of them, but that looks like a very interesting solution also.
Why HyperDex in particular? No exact reason; but lots of small reasons… the Mongo veneer API and ACID compliance being the two primary ones (and which makes TokuMX also suitable for my needs).
Also, over the next few months, I’m going to be moving into shard testing of various bioinformatics datasets; and will probably be hacking on the mongo, minimongo, and mongo-livequery packages. Writing a hyperdex, hyperdex-livequery, and minidex package would be the kind of exercise that would require me reading through and understanding the existing mongo drivers, and getting my knowledge of livequery up to the point where I could then hack on the mongo packages themselves.